Bee Cool Glass Coatings, Window Tint Glossary of Terms
We use a lot of terminology referencing our products and processes that may be unfamiliar to the general reader. We have included a glossary of terms to aid in understanding our literature a bit better.
A
Abrasion Resistant Coating
A coating on the surface of many window films, applied during the manufacturing process, that resists abrasion; it is usually hard.
Absorptance
The portion of solar energy that is absorbed by the glazing expressed as a decimal.
Absorption
The portion of solar energy that is absorbed by the glazing expressed as a percentage.
Acid Etched / Privacy Film
An effect obtained by specialist window film similar to acid etched glass that diffuses light but keeps the visible light transmission to high levels.
Annealed Glass
Glass is made by a process of heating and mixing its constituents; annealed glass is produced from the hot liquid as a thin sheet, which is allowed to cool and harden under controlled conditions.
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b Value
A measure of the amount of solar energy that enters the building by reflection and by absorption/re-radiation compared to the performance of 3mm clear glass; it was used particularly in Germany but has been superceded by the European standard g value.
Biaxially Oriented Film
Film that has been stretched in both the machine and transverse directions.
Blackout Film
Film, black in colour, that has visible light transmission close to 0% (typically < 0.25%).
Blast Film for Windows
A coating applied to glass to mitigate an unexpected blast. Blast films make glass safer from the threat of a bomb blast, plant explosion or wind storm. In a blast situation, most casualties happen because of flying glass. Bomb blast window film is the LEASE EXPENSIVE option to offer real protection in the event of a bomb blast or explosion close to your facility. It is highly effective when installed correctly. You should make sure the product that you choose meets a GSA Level 2 rating and is installed correctly. After the blast mitigation coating is installed, the edges should have 3/4 impact adhesive (such as Dow 995) installed.
Break Strength
The ability of window film of a given type and thickness to resist breaking. The measurement is given in terms of force per unit width, such as Newtons per 25mm or Pounds per Inch. Break strength varies greatly with film thickness and substrate type and is used to demonstrate the absolute strength of a strip of the material of a given width.
BTU Meter
A device that measures solar energy intensity and gives solar intensity in either W/m^2 or BTU/ft^2 hour. It is used to compare the solar intensity entering through glazing with and without solar control window film.
BTU-British Thermal Unit
The amount of heat energy required to raise the temperature of one pound of water on degree Fahrenheit. 1 BTU = 252 Calories (Cal). The BTU has been superseded by the metric Joule; 1 BTU - 1054.35 Joules.
Business Window Tint
Window tint can be used on interior office windows to create privacy or for aesthetics. For windows on the exterior of a business, you cannot use a window tint; a sun control glass coating must be used instead. Due to the way commercial windows are made and the type of glass that is used in them, standard window tint will wreck the building's windows and void the warranty. Sun control glass coatings are designed to reflect the sun's heat and UV rays back outside. Not all glass coatings are safe for every type of glass and commercial window. ALways make sure to have a sun control glass coatings expert come to your home and find a coating that is safe for your windows.
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Carbon Emissions
Emissions of carbon dioxide occur when fuels such as oil, gas and coal are burnt; carbon dioxide emissions are widely accepted as causing global warming; window film can reduce demands for cooling buildings and thereby reduce carbon emissions.
Colour Rendering Index
A measure of how much a glazing product changes the colour of natural daylight passing through the glazing on a scale of 0-100; an index of > 95 indicates suitability for even the most demanding of conservation requirements.
Containment System
A system that provides a means of additionally securing a safety film + glass combination to the frame, for example by adhering to both the film and the frame.
Core
A plastic tube or a resin impregnated cardboard tube used to hold window film.
Cross Direction
The direction across the width of a roll of window film.
Cure Time
The time required for the water used in the installation solution to evaporate from between the film and the glass and for the film's adhesive system to reach maximum bond strength.
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Decibel (dB)
A unit of power loss or attenuation used in EMI/RFI shielding: 1 decibel = 10 log (Power in / Power out). 3 dB attenuation is a fifty percent power reduction.
Detackified Pressure Sensitive (DPS) Adhesive
Pressure sensitive adhesive is sticky to the touch and remains so during its lifetime. It provides faster adhesion to glass than dry adhesives but durability can be lower; a small amount of optical distortion may be present, especially for safety and security film. DPS (Detackified Pressure Sensitive) adhesives are simply PS adhesives coated with a water soluble layer (intended to prevent the film from sticking to itself as the liner is removed) which must be washed away before the film installation. Cure for PS film averages three says, though this time is a function of temperature, humidity, and film type and may require up to 30 days in some situations. Some safety and security film can take longer to achieve full cure but this should not be confused with time to achieve performance.
DGU
Double Glazed Unit, also known as double glazing. Modern forms contain coatings and/or gas fillings to improve their insulating properties and are known as IGUs or Insulating Glass Units.
Direct Solar Reflectance
The portion of solar energy that is reflected by the glazing expressed as a decimal.
Direct Solar Reflection
The portion of solar energy that is reflected by the glazing expressed as a percentage. Not to be confused with Total Solar Energy Rejection.
Direct Solar Transmission
The portion of solar energy that passes directly through the glazing into the building expressed as a percentage.
Direct Solar Transmittance
The portion of solar energy that passes directly through the glazing into the building expressed as a decimal.
Double Glazing
See Insulating Glass Unit
Dry Adhesive
An adhesive that is initially dry to the touch but is activated by water; pressure sensitive adhesives are sticky to the touch. It provides a very hard and extremely durable chemical bond to the glass with no optical distortion which can sometimes occur with thicker PS adhesives. Used in window film for architectural applications for maximum durability and optical clarity. Cure time can vary according to film type, temperature, and humidity but in reasonable environmental conditions is normally about 7 days.
Dual Reflectance
A window film that has higher visible light reflectance to the outside that to the inside in order to improve ease of viewing to the outside, especially at night.
Dyed Film
A window film with a colour added within its structure.
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E-Beam Deposition
A manufacturing process used to deposit layers of metal or alloys (even those with high melting points) onto polyester film surfaces using an electron beam; very fast deposition rates are possible.
Edge Retention System
A system that provides a means of additionally securing a safety film + glass combination to the frame, for example by adhering to both the film and the frame.
Electromagnetic Radiation
Electromagnetic radiation concerned with glazing includes UV light, visible light, infra red heat; solar radiation contains all these components. Solar radiation concerned with glazing is not radioactive.
Electromagnetic Spectrum
The electromagnetic spectrum includes infra-red energy, visible light and UV light. It includes wavelengths from more than 100,000 kilometres (with a frequency of 3 Hertz) to wavelengths of 0.000000001 millimetres (with frequencies of > 1020 Hertz). The solar radiation that reaches Earth is a very small part of this range, typically 300 - 2500 nm (0.0000003 to 0.0000025 metres).
Electron Beam (E-Beam) Deposition
A manufacturing process used to deposit layers of metal or alloys (even those with high melting points) onto polyester film surfaces using an electron beam; very fast deposition rates are possible.
Elongation at Break
The percent increase in length of a sample of film at break when tested according to a recognized test method. Elongation is the film's ability to stretch without breaking.
Elongation at Yield
The percent increase in length of a sample of film at yield when tested according to a recognized test method. Elongation is the film's ability to stretch without breaking.
Emissivity
A measure of the ability of a surface to absorb and re-radiate energy; in simple terms, emissivity is the fraction of long wave infra-red energy remaining after reflection back to the source. A low value reduces the rate of heat flow through the glazing; window film can reduce emissivity of glazing to less than 0.4. Example: An emissivity of 0.33 means that 67% of the long wave infra-red energy is reflected back to the source.
EN Standards
Common standards agreed and published by European organisations such as the Comité Européenne de Normalisation (CEN). These standards must then be incorporated into national standards of European countries and must replace national where applicable.
EWFA
The European Window Film Association is a confederation of window film manufacturers that seeks to further the interests of the window film industry. It was established in 2000 by 3M, Bekaert, CPFilms, FTI and Madico, and brings together manufacturers and distributors with the purpose of promoting window film products in the EU and highlighting their innovative performances and properties as well as introducing the concept of EU harmonised or EU endorsed window film standards as no such standard presently exists in the European Union.
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Fading and Fade Reduction
Fading is seen as colour changes in fabrics, paintings, furniture, etc. and is caused bt ultra violet light, visible light, infra red energy, air humidity and other factors. Fading cannot be stopped but the rate of fading can be reduced. Window film can help reduce fading, for example by reducing UV transmissions to < 0.1%. Materials that fade quickly in sunlight cannot normally be protected sufficiently by window film against fading.
Far Infra-Red
Wavelengths of electromagnetic radiation range from 780 nm to about 60,000 nm. Near infra-red is about 780 - 2500 nm, while far infra-red is about 2500 - 60,000 nm. Solar radiation contains a large amount of near infra-red radiation between 780 nm to 2500 nm; room energy (room heat) is normally felt in the far infra-red region. Infra-red radiation is not radioactive.
Film Thickness
Thickness of window film is usually measured in microns (millionths of a metre or thousandths of a millimetre).
Film to Glass Thermal Stress Compatibility
There is a wide range of window film that is suitable for installation to existing new glazing. However, in some situations an incorrectly specified window film can cause thermal stress breakage of float glass. Window film manufacturers provide good guidelines on the thermal stress compatibility of each of their films with different glazing systems. Note that glass always has a risk of thermal stress breakage whether window film is installed or not; this risk is insignificant for tempered glass, negligible for heat strengthened glass, and low for float glass. The installation of correctly specified window film will maintain the risk of thermal stress breakage to low levels, provided that the glass is undamaged and meets accepted standards.
Fire Safety
Window film, if correctly installed, when burnt has low risk of propagating and spreading a fire, low toxicity, and low smoke emission.
Float Glass
Float glass made by the process developed by Pilkington using hot liquid tin - the hot liquid glass floats on the liquid tin surface. The hot glass is slowly cooled to release internal stresses from the glass and thereby enable the glass to be used in other processes such as cutting to specified sizes. Over 90% of annealed glass worldwide is made by the float method.
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g Value
The total amount of solar energy that goes to the inside of the building by reflection and by absorption / re-radiation; window film can modify glazing and give g values less than 0.20 and in some cases less than 0.10. Occasionally, the g value is given as a percentage but this is not strictly in accordance with EN standards. See also EN Standards.
Gasket
A plastic or rubber insert used around the perimeter of a window to prevent contact between the glazing and the frame; it is often also used as a weather seal.
Gauge
Thickness of window film is usually measured in microns (millionths of a metre or thousandths of a millimetre).
Glare Reduction
The percentage reduction in the amount of visible light transmitted by the glazing compared with that transmitted by 3 mm clear glass; window film can provide glare reduction of up to 95%.
Glass Strength
Glass does not have one specific strength but a range of strengths. Glass strength is dependent upon a number of factors including thickness, type, processing conditions, and whether it is damaged or not. Type of glass: As a guide, heat strengthened glass is up to 3 times stronger than float glass and tempered glass is up to 5 times stronger than float glass.
Glass Surface
Glazing surfaces are counted starting at the exterior surface and finishing at the interior surface; a double glazed unit of two panes of glass separated by an air space has four glass surfaces.
Global Warming
The effect identified by scientists of world temperatures increasing because of carbon dioxide emissions from the burning of coat, oil, gas and other fuels. Sometimes called the Greenhouse Effect of the Earth.
Graffiti
Unwanted damage to glass and other surfaces by scratching, painting, etching and other means; window film can protect glass and other surfaces against graffiti.
Greenhouse Effect
The effect where the interior of buildings, vehicles, etc. increase in temperature by the transmission of solar radiation through the glazing but, because glazing is more opaque to long wave than short waves of infra-red energy, this heat cannot escape easily and the interior compartment increases in temperature, often to uncomfortable levels.
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Hazard Rating
A system of rating the hazard produced from glass shattered in an explosion. Hazard ratings are obtained from standardized tests and range from No Hazard to High Hazard.
Heat Loss Reduction
An amount of energy is transferred through glazing by conduction, convection and radiation; the higher the rate of energy transfer, the greater the heat loss in the winter. The addition of an insulating window film to a glazing system reduces the loss of energy, ie. reduces heat loss usually from the building to the outside, and is expressed as a percentage.
Heat Mirror
A window film that has high visible light transmission relative to its solar energy rejection. These films are solar control products and are also termed spectrally selective products because they select for high visible light transmission and reduced solar energy transmission.
Heat Strengthened Glass
A glass that has been through an additional heat treatment process to make it 2 - 3 times stronger than annealed glass.
Home Window Tint
House windows need to have a sun control glass coating installed on them. Home window tint does not truly exist. Due to the way residential windows are made and the type of glass that is used in them, standard window tint will wreck home windows and void the warranty. Sun control glass coatings are designed to reflect the sun's heat and UV rays back outside. While they do absorb some of the sun's energy, the amount absorbed is safe for the glass. Not all glass coatings are safe for every type of glass. Always make sure to have a sun control glass coatings expert come to your home and find a coating that is safe for your windows.
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IGU
Glazing constructed from two panes of glass; the main use of insulating glass is to reduce the rate of heat flow through the glazing. Insulating Glass Units are often used to reduce heat loss from buildings in the winter, but are also used in hot climates to reduce solar heat gain by the building. Modern Insulating Glass units have coatings on one or both surfaces that face in towards the space between the two panes of glass; these coatings reduce energy transfer through the glazing and are nowadays significant in reducing energy consumption.
Infra-Red Radiation
Wavelengths of electromagnetic radiation from 780 nm to about 60,000 nm; near infra-red is about 780 - 2500 nm and far infra-red is about 2500 - 60,000 nm. Solar radiations contains a large amount of infra-red radiation between 780 nm to 2500 nm. This type of radiation is not radioactive.
Installation
The process of installing a window film to glass using an appropriate installation solution; correct installation by trained professionals is essential to ensure good performance and durability of the window film.
Installation Solution
Solution used during the installation of window film; it is specifically used to assist with film positioning and to prevent too-fast adhesion of the film to the glass.
International Window Film Association
The International Window Film Association is an organization that provides consumers with information on window film so they can make an educated decision on the product they would like and what they should look for in a service provider. Back To Top
K
K Value
K Value is an obsolete term and has been replace by the U Value.
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Laminated Film
Window Film made from two or more layers of polyester or other film adhered together with an adhesive.
Laminated Glass
Laminated glass is made from two or more pieces of glass with a plastic interlayer, usually polyvinylbutyral (PVB). Annealed, heat strengthened or tempered glass can be used to produce laminated glass. Laminated glass, if constructed correctly, is a safety glass and is designed to either not break or to break safely upon impact with a low risk or injury from broken glass fragments.
Longitudinal Direction
The direction across the width of a roll of window film.
Low-E
An abbreviation for Low - Emissivity
Low-E or Insulation Film
Window film with low emissivity coating(s) designed to reduce heat loss through glazing.
Luminous Efficacy
A measure of how effective a glazing product is in rejecting solar energy but retaining good visible light transmission. A number greater than 1.0 indicates that the film or glazing unit is "spectrally selective", blocking more of the near infra-red than the visible light components of the solar spectrum. It is calculated according to the equation LSG = visible light transmittance / g value.
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Machine Direction (MD)
The direction along the length of a roll of window film.
Metallizing
A manufacturing process used to deposit a metal onto polyester film surfaces by evaporation the metal is usually aluminum. Metallized window film provides excellent solar control.
Micron
One millionth of a metre or one thousandth of a millimetre.
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Nanometre or nm
One millionth of a millimetre or 0.000000001 m.
Near Infra-Red
Wavelengths of electromagnetic radiation range from 780 nm to about 2500 nm. Near infra-red is about 780 - 2500 nm while far infrared is about 2500 - 60,000 nm. Solar radiation contains a large amount of near infra-red radiation between 780 nm to 2500 nm; room energy (room heat) is normally felt in the far infra-red region. Infra-red radiation is not radioactive.
Neutral Colour
Usually refers to film that has a high Colour Rendering Index (> 90).
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Optical Properties
Solar-Optical properties of glazing - including window film on glass - are determined in accordance with EN 410 "Glass in building. Determination of luminous and solar characteristics of glazing". According to EN 410, the most important values are the visible light transmission and the g value. Other properties such as solar energy transmission, visible light reflection, etc. can also be obtained usin EN 410.
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Pascal
The metric unit of pressure, abbreviated Pa. 1 Pascal = 1 Newton / m^2. Tensile strength is usually measured in millions of Pascal or MegaPascal, abbreviated MPa.
Peel Strength
The adhesive strength of a window film in grams per 25 mm width, and is usually tested in accordance with an appropriate standard. It is generally measured as the force required to peel the film from the glass using a peel angle between the film and the glass of close to 180 degrees. Safety and security film has high peel strength.
Performance Time
The time required for safety and security film to achieve a minimum level of safety performance to an impact test such as EN 12600. This can be as low as a few hours but very thick and/or metallized and/or sputtered version can take 1-3 days. Installation quality has a very significant effect on the time needed to achieve a minimum level of performance.
Polyester Film (PET)
Polyester, as a biaxially oriented film, is the main constituent of window film; it has excellent optical clarity and strength. Its chemical name is polyethylene terephthalate, abbreviated to PET.
Polyvinyl Butyral
PVB, or Polyvinyl Butyral, is a material used to adhere glass layers together to make traditional laminated glass. Window safety film can be adhered to the surface of existing glazing to modify the glazing to a safety material with breakage like laminated glass.
Pressure Sensitive Adhesive (PSA)
Pressure sensitive adhesive is sticky to the touch and remains so during its lifetime. It provides faster adhesion to glass than dry adhesives but durability can be lower; a small amount of optical distortion may be present, especially for safety and security film. DPS (Detackified Pressure Sensitive) adhesives are simply PS adhesives coated with a water soluble layer (intended to prevent the film from sticking to itself as the liner is removed) which must be washed away before the film installation. Cure for PS film averages three days, though this time is a function of temperature, humidity, and film type and may require up to 30 days in some situations. Some safety and security film can take longer to achieve full cure but this should not be confused with time to achieve performance.
Privacy Film
Window film that, once correctly installed, reduces or prevents vision through glazing.
Puncture Strength
The puncture strength of a window film is given in kilograms or pounds. It is generally measured using a standardized test method as the resistance the film gives to a blunt probe forced through it.
PVB
PVB, or Polyvinyl Butyral, is a material used to adhere glass layers together to make laminated glass.
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Release liner
A disposable plastic film covering and protecting the adhesive layer on the window film.
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Sacrificial Window Film
Window film used to protect glass surfaces from accidental damage or deliberate attack, also known as Anti-Graffiti film. Sacrificial film can protect from scratching, 'tagging', acids including etching acid, paint, felt tip pens, and other graffiti. The cost of removal and replacement is often very much less than the cost of replacing the glass. Public transport vehicles need not be taken out of service for long periods of time; the potential for savings by avoiding repeated glazing replacement can be significant.
Safety and Security Film
Window film that, when correctly installed to glass, modifies the glass to one or more of the following:
- A safety glazing material resistant material according to a recognized standard such as EN 12600 "Glass in building. Pendulum test. Impact test method and classification for flat glass";
- A security glazing material resistant to manual attack according to a recognized standard such as EN 356 "Glass in building. Security glazing. Testing and classification of resistance against manual attack";
- A security glazing material resistant to bullet attach according to a recognized standard such as EN 13541 "Glass in building - Testing and classification of resistance against explosion pressure".
Window film has been extensively used for protection against deliberate attack on glazing, and is regularly specified by governments and commercial organizations for protection against glass shattered in an explosion.
Safety Glazing
Glazing which complies with the requirements of an impact test; EN 12600 is the European standard for assessing safety glazing. Window film is normally used to modify float glass to safety glazing materials; window film has been extensively tested to prove compliance with EN 12600 on a variety of float glass thicknesses.
Scratch or Abrasion Resistant Coating
A coating on the surface of many window films, applied during the manufacturing process, that resists abrasion; it is usually hard.
Security Glazing
There are various types of security glazing and specification needs to be careful to ensure the correct type is selected. Security glazing can resist manual attack (EN 356), reduce the effects of an explosion, or reduce the effects of bullet attack.
Shading Coefficient
A measure of the amount of solar energy that goes to the inside of the building by reflection and by absorption / re-radiation compared to the performance of 3 mm clear glass; it is being superceded by the g value.
Solar Control
Reduction by the glazing of the amount of solar energy passing through the glazing.
Solar Control Window Film
Window film that, once correctly installed, provides Solar Heat Gain Reduction, Glare Reduction, Fading and Fade Reduction, or a combination of these properties. Benefits include reduced summer temperatures inside buildings, reduced air conditioning costs, reduced eye strain, and reduced fading and damage to paintings, furniture, carpets, etc.
Solar Energy
The energy from the sun reaching the Earth's surface; it is generally in the wavelength range of 300 -2500 nm. This type of radiation is not radioactive.
Solar Energy Absorbance
The portion of solar energy that is absorbed by the glazing expressed as a decimal.
Solar Energy Absorption
The portion of solar energy that is absorbed by the glazing expressed as a percentage.
Solar Energy Damage
UV is not the only cause of fading and damage to property; visible light and infra-red energy also cause damage.
Solar Energy Reflectance
The portion of solar energy that is reflected by the glazing expressed as a decimal.
Solar Energy Reflection
The portion of solar energy that is reflected by the glazing expressed as a percentage. Not to be confused with Total Solar Energy Rejection.
Solar Energy Rejection
The total amount of solar energy that goes to the outside of the building by reflection and by absorption / re-radiation.
Solar Energy Transmission
The portion of solar energy that passes directly through the glazing into the building expressed as a percentage.
Solar Energy Transmittance
The portion of solar energy that passes directly through the glazing into the building expressed as a decimal.
Solar Factor
The total amount of solar energy that enters the building by reflection and by absorption / re-radiation; it is the same as the g value but is often given as a percentage, meaning Solar Factor % = g x 100. Window film can modify glazing to give g values less than 0.20 and in some cases less than 0.10. See also EN Standards.
Solar Heat Gain
The solar energy gained by a building from the sun and experienced as heat and / or as a temperature increase. Solar control window film can give significant reduction in solar heat gain.
Solar Heat Gain Coefficient
The total amount of solar energy that enters the building by reflection and by absorption / re-radiation; it normally refers to American methods of calculating a value similar to the European g value. Window film can modify glazing to give g values less than 0.20 and in some cases less than 0.10. See also EN Standards.
Solar Heat Gain Reduction
The reduction in solar energy gained by a building from the sun, often by the addition of Solar Control Window Film.
Solar Overheating
This occurs when solar energy entering the building causes room temperatures to be too high for workplace comfort. Solar control window film can considerably reduce solar overheating.
Solar-Optical Properties of Glazing
Solar-Optical properties of glazing - including window film on glass - are determined in accordance with EN 410 "Glass in building. Determination of luminous and solar characteristics of glazing". According to EN 410, the most important values are the visible light transmission and the g value. Other properties such as solar energy transmission, visible light reflection, etc. can also be obtained using EN 410.
Spectrally Selective
Glazing that allows high visible light transmission with good solar energy rejection. See Luminous Efficiency.
Sputtering
A manufacturing process used to deposit layers of metal, alloys, oxides, etc. onto polyester film surfaces; the process itself does not make the product better than metallized film, but the metals, alloys, etc. offer alternative properties to aluminum.
Strength of Glass
Glass does not have one specific strength but a range of strengths. Glass strength is dependent upon a number of factors including thickness, type, processing conditions, and whether it is damaged or not. Type of glass: As a guide, heat strengthened glass is up to 3 times stronger than float glass and tempered glass is up to 5 times stronger than float glass.
Sun Control Glass Coatings
Sun control glass coatings, also known as window film, are used on residential and commercial flat glass to help with reducing heat, UV rays, glare, fading and increasing privacy when needed.
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Tempered Glass
Glass, treated by heating and rapid cooling, to make it 3-5 times stronger than annealed glass.
Tensile Strength
The maximum force per original cross section area that a material resists before breakage when tested according to a recognized test method. The Tensile Strength of a material should not vary with thickness (for the same material of the same composition), but does for polyester film of different thickness because of some variation in the crystallinity of polyester film with thickness.
Thermal Comfort
The condition, including reasonable temperature and glare levels, that allows building occupants to be comfortable with the environmental conditions. Solar control and insulation window film can give significant improvements in thermal comfort.
Thermal Stress
Stress in a glass pane caused by one part of the glass pane being at a different temperature from another part of the same glass pane.
Thermal Stress Breakage
A break in glass that is caused by thermal stress; the typical feature of a thermal stress breakage in glass is that the break commences at 90 degrees to the edge of the glass. All glass has a risk of breakage due to thermal stress regardless of whether window film is applied or not; this risk is insignificant for tempered glass, negligible for heat strengthened glass, and low for float glass. See Thermal Stress Compatibility.
Thermal Stress Compatibility
There is a wide range of window film that are suitable for installation to existing and new glazing. However, in some situations an incorrectly specified window film can cause thermal stress breakage of float glass. Window film manufacturers provide good guidelines on the thermal stress compatibility of each of their films with different glazing systems. Note that glass always has a risk of thermal stress breakage whether window film is installed or not; this risk is insignificant for tempered glass, negligible for heat strengthened glass, and low for float glass. The installation of correctly specified window film will maintain the risk of thermal stress breakage to low levels, provided that the glass is undamaged and meets accepted standards.
Thermal Stress Strength of Glass
In normal architectural and automotive uses: tempered glass will not break from thermal stress, heat strengthened glass is very unlikely to break from thermal stress, but float glass is susceptible to breakage from thermal stress. When adding a window film to existing glazing, the supplier should always check the glazing for thermal stress compatibility between the window film and the glazing.
Tinted Film
A window film with a colour added within its structure.
Total Solar Absorption
The portion of solar energy that is absorbed by the glazing expressed as a percentage.
Total Solar Energy Rejection
The total amount of solar energy that goes to the outside of the building by reflection and by absorption / re-radiation.
Total Solar Reflection
The portion of solar energy that is reflected by the glazing expressed as a percentage. Not to be confused with Total Solar Energy Rejection.
Total Solar Transmission
The portion of solar energy that passes directly through the glazing into the building expressed as a percentage.
Toughened Glass
Glass, treated by heating and rapid cooling, to make it 3-5 times stronger than annealed glass.
Transverse Direction (TD)
The direction across the width of a roll of window film.
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U Value
The U value is a measure of the rate of heat transfer through the glazing (or other building material) and is given in units of W/m^2.K. A method of calculating the U value of glazing is given in EN 673 "Glass in building. Determination of thermal transmittance (U value). Calculation method".
UV Transmission
The portion of Ultra Violet light that passes directly through the glazing into the building expressed as a percentage.
UV Transmittance
The portion of Ultra Violet light that passes directly through the glazing into the building expressed as a decimal.
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Vapour Deposition
There are several different definitions of vapour desposition. For example, metallizing can be regarded as a form of physical vapour deposition where Aluminum metal is evaporated as a vapour onto polyester film; sputtering uses an ionized plasma that some people regard as a vapour. Chemical vapour deposition (CVD) deposits atoms (or molecules) from a chemical vapour.
Visible Light Reflectance
The portion of visible light that is reflected by the glazing expressed as a decimal. Usually the visible light reflectance is given for both exterior and interior sides of the glazing.
Visible Light Reflection
The portion of visible light that is reflected by the glazing expressed as a percentage. Usually the visible light reflection is given for both exterior and interior sides of the glazing.
Visible Light Transmission
The portion of visible light that passes directly through the glazing into the building expressed as a percentage.
Visible Light Transmittance
The portion of visible light that passes directly through the glazing into the building expressed as a decimal.
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Window Film
Window film is a self-adhesive film that is applied to glass and glazing systems to modify the properties of the glass / glazing. The properties that can be modified include solar control, safety, security, privacy, insulation, UV filtering and rade reduction, and decorative.
Window Tint
Window tint is a film that is applied to vehicle windows to darken the glass. This product cools the vehicle by absorbing the sun's rays. Vehicle windows are single pain so the heat then radiates from the glass both outside and inside. The product is made from polyester that is dyed and has an adhesive and anti-scratch coating applied to it. These products are not to be used on home and business windows. The amount of heat they absorb from the sun will damage the glass and window as a whole. For home window tint lease see "Home Window Tint". For business window tint please see "Business Window Tint".
Window Tinting
Window tinting is the process of installing a window tint onto a piece of glass. There are many different qualities of window tint that a window tinting company can install on a vehicle. Window tinting home or commercial windows is not recommended. If you're looking for window tinting of home and business windows see our sun control glass coatings page. These commercial window films and residential window films are made for the type of glass and window frames found in your home or office.
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Yield Point
The point at which material, when deformed by an applied force, can no longer contract back to its original shape; normally determined according to a recognized test method. Various properties can be used to determine the Yield Point, such as Yield Strength, refractive index and size. Yield Strength is normally used for polyester film.
Yield Strength
The maximum force per original cross section area that a material resists before it reaches it Yield Point when tested according to a recognized test method. The Tensile Strength of a material does not vary with thickness (for the same material of the same composition, test in the same direction and under the same conditions).
